This is a long article: http://www.leangains.com/2010/07/truth-about-alcohol-fat-loss-and-muscle.html. But it is a fantastic read and it is thoroughly researched.

The TL:DR version is he has a great protocol for minimizing drinking's damage to your body goals at the end of the article so that you can be a normal person who has an occasional drink without it setting you back. Plus there is some support that an occasional red wine is healthful.

Basically, because alcohol is metabolized first due to its toxicity, fats aren't metabolized upon consumption (even if you're in a caloric deficit...) and are transported into fat storage instead (similar story for carbs). However, alcohol itself can't be turned into fat. It's the drunk munchies and highly caloric drinks that kill it. Thus: eat a lot of protein w/ fiber before drinking so you're not hungry, then drink unsweetened alcohols with noncaloric mixers, or red wine. Ciders are your 3rd choice (not the 30g of sugar ciders though... dry ciders). Alcohol will make you shed water so you'll look more cut the day after anyways.

So boys, you can drink occasionally following these rules with minimal disruption to your gains.